feat: add the solution of Plus One(066) with kotlin.

Author: relish-wang

README.md

@@ -41,7 +41,7 @@
 | [038][038-question] | [Count and Say][038-tips]                                    | [✅][038-java] |              | [✅][038-kotlin] |
 | [053][053-question] | [Maximum Subarray][053-tips]                                 | [✅][053-java] |              | [✅][053-kotlin] |
 | [058][058-question] | [Length of Last Word][058-tips]                              | [✅][058-java] |              | [✅][058-kotlin] |
-| [066][066-question] | [Plus One][066-tips]                                         | [✅][066-java] |              |                  |
+| [066][066-question] | [Plus One][066-tips]                                         | [✅][066-java] |              | [✅][066-kotlin] |
 | [067][067-question] | [Add Binary][067-tips]                                       | [✅][067-java] |              |                  |
 | [069][069-question] | [Sqrt(x)][069-tips]                                          | [✅][069-java] |              |                  |
 | [070][070-question] | [Climbing Stairs][070-tips]                                  | [✅][070-java] |              |                  |
@@ -481,4 +481,5 @@
 [038-kotlin]: ./src/_038/kotlin/Solution.kt
 [053-kotlin]: ./src/_053/kotlin/Solution.kt
 [058-kotlin]: ./src/_058/kotlin/Solution.kt
+[066-kotlin]: ./src/_066/kotlin/Solution.kt
 [771-kotlin]: ./src/_771/kotlin/Solution.kt

src/_066/kotlin/Solution.kt

@@ -0,0 +1,41 @@
+package _066.kotlin
+
+import java.util.*
+
+/**
+ * @author relish
+ * @since 2018/04/19
+ */
+class Solution {
+    fun plusOne(digits: IntArray): IntArray {
+        var flag = 1
+        val len = digits.size
+        for (i in len - 1 downTo 0) {
+            digits[i] += flag
+            if (digits[i] >= 10) {
+                digits[i] %= 10
+                flag = 1
+                continue
+            }
+            flag = 0
+            break
+        }
+        if (flag == 1) {
+            return IntArray(len+1,fun(index: Int):Int{
+                if(index==0)return 1
+                return digits[index-1]
+            })
+        }
+        return digits
+    }
+}
+
+fun main(args: Array<String>) {
+    println(Arrays.toString(Solution().plusOne(intArrayOf(9, 9, 9, 9))))
+}
+//val ret = IntArray(len + 1)
+//ret[0] = 1
+//for (i in digits.indices) {
+//    ret[i + 1] = digits[i]
+//}
+//return ret

tips/066/README.md

@@ -15,6 +15,7 @@ The digits are stored such that the most significant digit is at the head of the
 
 题意是给你一个数字数组，高位在前，并且首位不为 0 除非这个数组就是 `[0]`，让你给该数组低位加一求其结果，那么我们就模拟小学数学那样进位去算即可，如果一直进位到首位，这种情况也就是都是由 9 组成的数组，此时我们只要 new 出一个多一个长度的数组即可，并把第 0 个元素赋 1 即可。
 
+Java:
 ```java
 class Solution {
     public int[] plusOne(int[] digits) {
@@ -37,6 +38,32 @@ class Solution {
 }
 ```
 
+kotlin(208ms/100.00%)
+```kotlin
+class Solution {
+    fun plusOne(digits: IntArray): IntArray {
+        var flag = 1
+        val len = digits.size
+        for (i in len - 1 downTo 0) {
+            digits[i] += flag
+            if (digits[i] >= 10) {
+                digits[i] %= 10
+                flag = 1
+                continue
+            }
+            flag = 0
+            break
+        }
+        if (flag == 1) {
+            return IntArray(len+1,fun(index: Int):Int{
+                if(index==0)return 1
+                return digits[index-1]
+            })
+        }
+        return digits
+    }
+}
+```
 
 ## 结语